Distillation of crude oils



Aug. l, 1933. n Ff'nNKER 1,920,815

DISTILLATIN OF CRUDE OILS Original Filed Febx. 9, 1927 Figi.

gq, @l @www ATTORNEYS Patented Aug. 1, 1933 Urrso STATES g g miensN YPTEr DISTllLLATION OF CRUDE A(NULS Frank Tinker, Streetly, England, assigner to Simy clair Refining Company, New York, N. Y., a Corporation of Maine Original application February v9, 1927, Serial No.

Divided and this application September 9, 1930, and in Great Britain April 28,1926.

Serial No., 480,716

Claims.

In the distillation of crude oils, (including topped oils, fueloils, and gas oils), shale oils, tars and the like, ymore particularly inL what are'l known as topping plants,l it is becoming increas-i ingly common to use heat exchange apparatus for the purpose of economizing fuel and also re-` ducing the amount of water cooling which is otherwise necessary.

The object of the present invention is yto provide a distillation system, combined with one of several cracking systems, in whichy heat exchange can be carried out morel effectively and economically and to affurther extent than is usual and in such a way that the different parts ofthe plant are capable oi independent control.

The invention comprises the use in thesystem, of a mixing chamber into which hot liquids or vapors or mixtures of liquidand vapor from different parts of the system are delivered and Amixed so as to attain acommon temperature prior. to their entering a separating chamber for liquid andv vapor, thus enabling outgoing heat derivediromfany part of the system' to be returned'toand'usefully employed in the system.

This application lis a'divisionof my prior applicationlSeral No.v 167,047 filed February` 9,

1927,` which has matured into Letters Patent' Number 1,779,222, granted October 21, 1930. `In the topping plant consisting of a fire-heated pipestill, a mixing chamber, a separating chamf ber, a pluralityfof fractionating towers and iractional condensers and acondenser yfor light disw tillates, illustrated in Figures l and 2 of my prior application,'hot residuum .from the separating chamber is taken as vheretofore through a heat Y exchanger in which` crude oil before entering the pipestill is subjected to a preliminary heating; hot refluxed oil from one or more of the iractional condensers is also passed through heat exchangers and caused to heat coldcrude oil which is passed next through acoil or pipes inserted in the iractional condensers for further heating and' is finally delivered to the mixing chamberfractonating columns and forced by a pump through a 1pressure still and, separating drum each `working under any 4desired pressure. Cracked liquid residue is Adischarged from the branch circuit, and the cracked vaporsare de-v livered into the mixing` chamber oi the main system.` 'Alternatively the residue from theseparating chamber ofl the system first described may be pumped through a still and separating drum, and the cracked vapors delivered into lthe,

mixing chamber.` i

By the use of` acommon mixing chamber, into which hot liquid or vaporor mixtures of liquid and vapor derived from diiierent partsfof the system can `be delivered, heat .given Iupl inthe cooling of distillates and residues may be utilized economically to reduce initial cost and upkeep charges in the nre-heated partof the system, and generallyto effect important economies in vthe operationof distillation plants.

The two `accompanying, diagrams illustrate diierent modes oi carrying my invention into effect.,

Figure I of my prior application shows a topping plant ,which is fed, instead of by one stream 80 of crude oil as is usual, by two streams of crude oil merging after preheating in the manner outlined below, into the mixing chamber a. In this chamber the streams commingle at the top, yand ing drum bA wherein the liquid oils oi the mixed stream are separated from the entangled vapors. The` crude oil stream flowing inthe pipe l is preheated on its way to the mixing chamber av changer c) with the liquid residuum nowing from the separating drum, and secondly by a fire-heated pipe-still d, where it can be raised to any desired temperature immediately before entering a. The crude oil stream in the pipe 2 isrpreheated `by a vapor heat exchanger f in which considerable volumes of the medium and heavier vapors liowing from the separating drum towards the water condenser g are iractionally condensed by means of a coil or pipes inserted therein through which flows the crude oil stream 2. i

On either side of the fractional Ycondenser or vapor heat exchanger it is convenient toV 105' place two fractionating columns fcl, and fcz, so that the grade of distillatecondensed in f can be controlled. y in the diagram is an ordinary water cooled" condenser which condenses the light oils escaping liquefaction in fel, f and fcz.` -110 It is clear that the coil or pipe area in j can iiow downwards over barile plates into a separat- 8 firstly by indirect heatexchange (in heat experature of the mixed stream can be controlled by imparting a little more or less heatas may be required to the crude oil stream i by means of the fire-heated pipestill d..

It is evident also that a supplementary indirect heat exchanger f2 between condensing vapors and a further crude oil stream Sfmay be s 1s kept at a pressure round about 500 los.

paced in the vapor path between Vfc? and, the Water condenser g as shown inj Figure S of' my prior application. If this were done it is advisable to pass this third stream of crude oily` kthrough a pipestill d2 before introducing` it into the mixing lchamber a.l

Figure l of the ypresent application illustrates onefform of the combined distillation cracking system in which the cracking ofI refiuxes is carried out partly in the liquid phase and thereafterv partly in the vapor phase. Re'uxed oils from f together if Adesired ,withy oils refiuxed froml either or both fol and fc2 are supplied by a pump p to a still l and cracked under` pressure inf-the liquid phase after which the oil is passed into'a vapor superheater kandffurther subjected to cracking while'` in the vapor state. A "loaded Valve V yset to vwork at a pressure sulicient to keep-the hydrocarbon oil in' a liquid statev isplaced in'a position between the liquid phase cracking still Z (preferably ofthe pipestill pattern and supplied by a pump pi) and a vapor superheater k2 following it. A separating drum may be placed in the branch circuit but is generally dispensed with as the extent or" cracking inthe liquid phase need not be carried so far as is otherwise necessary forl economical operation when the samel hydrocarbon is vto be further cracked subsequently in the vaporphase.v

Furthermore,l it has been found convenient as shown in Figure 2 of my present application, to'employ a branch circuit for' crackingreiiuxes which is builton the following lines.. Thev refluxes- 'are taken from the bottomsof the towers and forced by means of-a pump 'p4 through a preheater 1' and then `through' a lcontrary flow superheater s of similar design tofthat shown in my U.v S. Patent No. 1,393,184.V Thissuperheater comprises lan inner and outer tube the annular space between which container a helical partition for causingvthe'iiuid to flow along a helical path;` A loaded ValveI 'vlwis however, placed at the point Wherer the hydrocarbon oil returns in rthe space between the inner tube and the outer tubev which. latter is heated externally lbyv fire. The loaded valve o1 is set soas to keep the oil liquid or mostly so, whilst it is being heated in the preheatertosay 430 C. or thereabouts and subsequently whilst it is picking up still more heat in its passage throughthe inner tube of the cracking chamber.4 After the oil leaves the loaded valve it wholly Vaporizes in the, spacev between the inner and outer tube Whereit is further cracked inthe form of vapor.

It is evident that other methods of cracking involving superheating either in the liquid phase or vapor phase or both4 canbe applied to the in- Vention yby means of abranchcircuit. For instance the insertion of a loaded valve at a point between the outlet of the contrary iiow super- 4or liquid and foam consecutively as desired.

heater s of Figure 5 and the mixing chamber a enables hydrocarbon oil to be heated in such a system in two pressure stages, both stages being liquid, or liquid and vapor consecutively, In the" case in which the hydrocarbon oil is kept liquid-by pressure in both stages, much higher A pressures than are now usual can be applied 'during the rst stage to the oil flowing through r andl the inner tube of s, since a pressure is also being applied to the'outer surface oi' the inner tube of s. With suitable steel tubes it is possible to apply with safety pressures up to 1000 lbs. in r; and also inthe inner tube of s if the oil in the space betweenl thek inner and outer tube oi 'I-Ia'vi'ngi thus described my' invention what I clairnf asnew andV desire to secure by Letters Patent is Ythrough a fire-'heated heating Zone separate from the rst mentioned heating zone and heating'it to a cracking temperature under superatmospheric pressure therein, reducing the pressure' on `the hot oilvproducts discharged from this fire-heated heating Zone, passing a stream of these hot oil products under reduced pressure through another nre-heated heating zonescparate'from the first mentioned heating Zonev and heating it to a higher crackinnr temperature therein,V introducing the hot oil products lfrom the last mentioned nre-heated heating zoneinto the mixing zone and taking off vapors fromv the partialv condensation and condensing the same.

2.'In the distillation of mineral oils, the improvement which comprises passin'ga stream of raw oil through a heating zone into a mixing zone and heating'it to a distillation temperature the heating zone, introducing a hot oil mixture including this thus heated raw oil from the mixing zone into a separating zone, discharging residuum from the separating zone, taking off vapors from the separating zone and partially condensing the same by heat exchange with another stream of raw oil, introducing the thus preheated raw oil into themixing zone, passing a stream or condensate from this partial condensation through a hre-heated heating zone separate from the first mentioned heating zone andheating it toa cracking temperature under superatmospheric pressure therein, reducing the pressure on the'hot oil productsdischarged fromk this fire-heated heating zone, passing a vstream 'of these hot oil products under reduced pressure in the heating zone, introducing a hot oil mixture including this thus heated raw oil from the mixing zone into a separating zone, discharging residuum from'the separating Zone, taking off vapors fromv the separating Zone and partially condensing the same, passinga stream of condensate from this partial condensation through a fire-heated heating zone separate from the rst mentioned heating zone and heating it to a cracking temperature under superatmospheric pressure substantially in the liquid phase therein, reducing the pressure onthe hot oil products discharged from this fire-heated heating zone, passing a stream of these hot oil products under reduced pressure through another fire-heated heating zone separate from the first mentioned heating Zone and heating it to a higher cracking temperature substantially in the vapor phase therein, 'introducing the vhot oil products from the last mentioned iire-heated heating zone into the mixing Zone and taking oi vapors from the partial condensation and condensing the same.

4. In `the distillation of mineral oils, the imprvement which` comprises passing a stream of raw oil through ya heating Zone into a mixing Zone and heating, it to a distillation temperature in the heating zone, introducing a hot oil mixture including this thus heated raw oil from the mixing zone into a separating zone, discharging residuuin from the separating zone, taking off vapors from the separating zone and partially condensing the same, passing a' stream of condensate from this partial condensation through a heating zone separate from the first mentioned heating Zone and heating it to a cracking temperature under superatmospheric pressure therein, reducing the pressure on the hot oil products discharged from this heating lzone, passing ya stream of these hot oil products under reduced pressure through a fire-heated kheating Zone es"A separate from the first mentioned heating rone and heating it to a higher cracking temperature therein, the stream of condensate in the iirst mentioned separate heating zone being heated by indirect heat exchange with the stream of hoty oil products in said fire-heated heating zone, introducing the hot oil products from the last mentioned nre-heated heating zone rinto the mixing zone and taking off vapors from the partial condensation and condensing the same.

5. In the distillation of mineral oils, the improvement which comprises passing a stream of raw oil through a heating Zone into a mixing zone and heating it to a distillation temperature in the heating zone, introducing a hot oil mixture including this thus heated raw oil from the mixing zone into a separating zone, discharging residuum from the separating zone, taking off vaporsfrom the separating zone and partially condensing the same, passing a stream of condensate from this partial condensation through a heating Zone separate from the first mentioned heating zone and heating it to a cracking temperature under superatmospheric pressure substantially in the liquid phase therein, reducing the pressure on the hot oil products dischargedfrom this heating Zone, passing a stream of these hot oil products under reduced pressure through ya nre-heated heating zone separate from the first mentioned heating zone and heatingit to a higher cracking temperature substantially in the vapor phase therein, the stream of condensate in the rst mentioned separate heating zone being heated by indirect heat exchange with the stream of hot oil, products in said nre-heated heating zone, introducing the hot oil products from the last mentioned reheated heating zone into the mixing zone and taking 'oi vapors fromthe partial condensation and condensing the same.

` FRANK TINKER. 

